Clarification on the M54 and N52 engines for Z4

[NYZ4Jack]

OK, I'm in the market to buy a Z4 and a bit scared off from the later models due to engine valve issues in the N52 motors.

Looking at the specs online, I see that the 2005 3.0i models have a M54 engine which produces 225HP and the 2007 3.0i models have a N52 engine which produces 215HP.

That doesn't make sense to me. Then why wouldn't I get a 2005 which has the proven M54 motor with less issues and more HP? Any other significant difference between the 2005 and 2007 models beside the front bumper?

Thanks!

[vachss]

I believe that the 3.0i (highest spec non-M Z4) was replaced by the 3.0si, which made 255 hp out of the N52. The 3.0i N52 was the lower spec'd model - analogous to the older 2.5i. While many folks have had the lifter tick issue it is by no means universal. I've had my 3.0si since new in '07 and after 80K miles have never heard any lifter tick. If given the choice of Z4s again today I would definitely go for an N52 equipped 3.0si - light, torquey and also capable of very high cruising MPG (32-34 at 80 mph) when that's what you want.

[-c-]

Well the N52 is an amazing lil power plant, don’t forget its way lighter than the M54 so your front end feels lighter and steers better with less weight up front.

the lifter tick issue has shown no failure, though a pain and also not all cars suffer from it it was covered under a cpo if it did tick, most cars with the tick where fixed with a simple lifter replacement others required the check valve which needed a new head. but BMW sais that the ticking will not cause any failure. again not sure how I feel about that but the N52 is far and away a more modern engine. the down side is you can’t really put forced induction on it with the magnesium block where the M54 could.


3.0I (n52) 212HP 3.0sI (n52) 255HP after tune 265 to 275HP possable. european models had 265HP


The BMW N52 is a straight-6 engine made by BMW, which debuted in 2004 on the BMW E63 630Ci. The N52 is BMW's 12th generation production straight-6 engine.

Its crankcase is made entirely of magnesium and aluminum, a first in the world of engine construction. BMW used Alusil aluminum cylinder sleeves, which offer high heat conductivity, and cast them into a lightweight magnesium block [1], creating one of the lightest production engines of its size class in the world at 161 kg (354 lb). It includes BMW's second generation Valvetronic system and Double-VANOS for fuel-efficiency (12% fuel savings over the previous generation BMW M54 engine - and increases performance). Producing 63 kW (85.5 hp) per liter of displacement, it has the lowest weight per horsepower of any six cylinder engine (1.24 hp per kilogram with the latest version).

It was awarded as one of Ward's 10 Best Engines of the Year in 2006 and 2007. Technologically it is even more advanced than the new N54B30 bi-turbo, which is based on an older M54B30 design and lacks several improvements that BMW has made for this engine.

All BMW nameplates have been available with this engine in at least one version. Although the N52 have been replaced in some applications by the N53 (in Europe only) and biturbo N54 (for high-performance trims), both which add direct injection but do not use Valvetronic, the N52 remains a mainstay engine of BMW's lineup as of 2011, although it will be gradually replaced by the BMW N20.

[NYZ4Jack]

That was very informative guys. Thank you!

[pokeybritches]

If you ever want much more than stock horsepower, go with the M54. It shares its forged crank with the E36 M3, and there are already excellent forced induction options.

[vachss]

Originally Posted by pokeybritches

If you ever want much more than stock horsepower, go with the M54....

If you ever want much more than stock Z4 horsepower, save yourself a bunch of money and trouble and start with a Z4M. The non-M Z4's are great cars, but if you want gobs of hp there are far more efficient ways to go about it.

[pokeybritches]

It's much cheaper to mod a 3.0i to 330 hp than to buy a Z4M in the first place, especially if you don't care to spend the money on the other pieces that make up the Z4M - steering, brakes, LSD, etc.

[vachss]

Originally Posted by pokeybritches

It's much cheaper to mod a 3.0i to 330 hp than to buy a Z4M in the first place, especially if you don't care to spend the money on the other pieces that make up the Z4M - steering, brakes, LSD, etc.

Not busting your chops, but I'm really curious about this. What does a good reliable FI kit cost installed? And what does a decent M54 era Z4 cost? You can get an OK MR for something in the low $20s these days. Is a modded non-M really going to be that much cheaper?

Sure you could get a junker Z4 donor car, but you could probably find a beat to hell MR as well. For otherwise comparable levels of wear, mileage, etc. is modding a non-M really significantly cheaper than buying an M?

[pokeybritches]

Originally Posted by vachss

Not busting your chops, but I'm really curious about this. What does a good reliable FI kit cost installed? And what does a decent M54 era Z4 cost? You can get an OK MR for something in the low $20s these days. Is a modded non-M really going to be that much cheaper?

Sure you could get a junker Z4 donor car, but you could probably find a beat to hell MR as well. For otherwise comparable levels of wear, mileage, etc. is modding a non-M really significantly cheaper than buying an M?

No offense taken.

When I bought my Z4M, I was offered $8k for my Z4 with 90k miles because I had a carfax issue. The issue involved me being run off the road in the rain, and during the excursion several body panels and a strut were damaged. The repair shop that did the work for me was outstanding. However, because the car had "mechanical damage" the dealer said they would have to sell it at an auction, etc. My Z4 is in excellent condition otherwise, and it has been meticulously maintained. The trade in amount they offered me was admittedly low and the car had been extremely reliable, so I kept it as a toy to mod.

I know the trade in value of a 90k mile Z4 with a carfax issue is much lower than a pristine-looking CPO 30k mile Z4. Clean, low-mileage examples regularly go for less than $15k. Most M roadsters with 50k miles go for $25k or so. There's at least a $10k price difference across the board with similar miles.

I don't believe a 100k mile Z4 and 100k mile Z4M are necessarily in the same condition. A used M is more likely to have been tracked, and many say one track mile equals ten street miles in terms of wear and tear (obviously this varies by component). Folks have driven M54-based 3 series cars for 500k+ miles. The S54 engine is more strung out, and it simply doesn't last as long, especially in the conditions in which it's usually used. So, I'd argue that a standard Z4 can have higher mileage than a Z4M yet still be in the same condition (just my opinion).

As with almost anything, there's a cheap way and expensive way to do something. I could keep my $8k Z4 and throw on a $4500 VF Engineering supercharger kit (which will be available shortly) and call it a day. Or, I could pay a lot of money and have a shop install a twin screw setup on a low-mileage Z4. Either way, I think you'd end up paying thousands of dollars less for a car with similar straight-line performance that doesn't require the extra maintenance costs of M components.

Which is better? I don't know. I know I would still have ///Mvy if I wouldn't have bought my M, and I would miss my 3.0i if I had sold it. I like having a choice in the mornings, and each car effectively only gets half the miles put on it each year. In terms of cost, the cheaper route is definitely with the non-M and picking up a few used parts off the forums... unless you track the car and want the options the M offers. I do know the S54 screams, and the M feels much more like a sports car than the standard Z4, but it's much more expensive at the same time.

[Incompatible]

Another consideration is the handling aspects and what your plans are. The non-M cars are by no means poor performers, with a few mods their performance level exceeds the skill level of most drivers and will keep up with all but a small percentage of other cars. The M cars have the ability to fully use that extra power by means of their suspensions, brakes, and lsd. What are you looking for? A car to see a lot of track time? Buy the M. For an occasional canyon run and a fun all around car? By the Si. As most members here will tell you, there is more performance to be gained by spending money on driver classes then on our cars.

[MHeavNC]

I have both a N52 3.0i roadster and a M Coupe.. Wife drives the roadster daily.. Although the performance difference is very apparent, I am in love with both cars.. I have the new cylinder head on my roadster, and it is very quick and fun to drive.. I really love the engine!! The M is,... well,... Nasty!!! The SI would give you some of the nasty along with a awesome engine.. Test all three if you can, and buy the one that suits your performance and travel needs..